Pvt. Colton Mulroney is a soldier stationed at the safe zone in Tennessee.
Nothing is known about Colton before the infection, except that he was most likely a soldier, however this might not be true due to his low rank.
When the outbreak began, Colton somehow came to be at the safe zone.
Shortly before the firebombing, Colton made a very brief appearance when monitoring a radar.
At the beginning of Part 5, Colton is sent to alert the president of the arrival of Chew Toy, the helicopter piloted by Jeff and containing the rest of the group. When they are cleared, Colton runs back off to deliver the confirmation.
When Brian's group was detained, they were immediately screened and quarantined. Later, when Jack is found to be the former Alpha, President Craig Fitzpatrick took Colton's pistol and prepared to shoot Jack. Brian escaped his restraints and tried to help his dad, so Craig ordered Colton to grab the boy. When he did, however, Brian thrashed around and accidentally bit the soldier on the hand. Pvt. Mulroney dropped Brian and fell to the ground, starting to transform. Before he could, Craig shot him in the back of the head. By doing so, some of Colton's infected blood splashed into Craig's eyes, infecting him and ultimately leading to the deaths of several people.
- Brian (directly caused)
When Pvt. Mulroney grabbed Brian, the boy thrashed around and accidentally bit him. Seeing that the soldier had been infected, Criag walked up and shot him in the back of the head.
- Craig Fitzpatrick (indirectly infected)
- Jeff (indirectly caused)
- Will (indirectly caused)
- Janet (indirectly caused)
- Mary-Ann (indirectly caused)
- Ashley (indirectly caused)
- Duncan Shepherd (indirectly caused)
- He is the first soldier who is shown to be infected and killed
- He has a sister named Rebecca